Sustainability can be fun

How can we make use of the earth as a natural resource? How can sustainability actually be great fun? With a home dug into the ground, you can make use of earth's temperature, so the house will not heat up too much in the summer or cool down in the winter. With an outdoor shower, you are happy when it rains, so you can make use of free rain as a natural resource. With a slide you go down fast and gravity becomes your friend. These are just a few ideas dealing with sustainability in a fun way.